Revert "refactor(directives): remove binding.instance"

This reverts commit 52cc7e8231.

packages/runtime-core/__tests__/directives.spec.ts

@@ -9,6 +9,7 @@ import {
   DirectiveBinding,
   nextTick
 } from '@vue/runtime-test'
+import { currentInstance, ComponentInternalInstance } from '../src/component'
 
 describe('directives', () => {
   it('should work', async () => {
@@ -17,6 +18,7 @@ describe('directives', () => {
     function assertBindings(binding: DirectiveBinding) {
       expect(binding.value).toBe(count.value)
       expect(binding.arg).toBe('foo')
+      expect(binding.instance).toBe(_instance && _instance.proxy)
       expect(binding.modifiers && binding.modifiers.ok).toBe(true)
     }
 
@@ -105,9 +107,13 @@ describe('directives', () => {
       unmounted
     }
 
+    let _instance: ComponentInternalInstance | null = null
     let _vnode: VNode | null = null
     let _prevVnode: VNode | null = null
     const Comp = {
+      setup() {
+        _instance = currentInstance
+      },
       render() {
         _prevVnode = _vnode
         _vnode = withDirectives(h('div', count.value), [
@@ -147,6 +153,7 @@ describe('directives', () => {
     function assertBindings(binding: DirectiveBinding) {
       expect(binding.value).toBe(count.value)
       expect(binding.arg).toBe('foo')
+      expect(binding.instance).toBe(_instance && _instance.proxy)
       expect(binding.modifiers && binding.modifiers.ok).toBe(true)
     }
 
@@ -160,9 +167,13 @@ describe('directives', () => {
       expect(prevVNode).toBe(_prevVnode)
     }) as DirectiveHook)
 
+    let _instance: ComponentInternalInstance | null = null
     let _vnode: VNode | null = null
     let _prevVnode: VNode | null = null
     const Comp = {
+      setup() {
+        _instance = currentInstance
+      },
       render() {
         _prevVnode = _vnode
         _vnode = withDirectives(h('div', count.value), [
@@ -196,6 +207,7 @@ describe('directives', () => {
     function assertBindings(binding: DirectiveBinding) {
       expect(binding.value).toBe(count.value)
       expect(binding.arg).toBe('foo')
+      expect(binding.instance).toBe(_instance && _instance.proxy)
       expect(binding.modifiers && binding.modifiers.ok).toBe(true)
     }
 
@@ -284,6 +296,7 @@ describe('directives', () => {
       unmounted
     }
 
+    let _instance: ComponentInternalInstance | null = null
     let _vnode: VNode | null = null
     let _prevVnode: VNode | null = null
 
@@ -294,6 +307,9 @@ describe('directives', () => {
     }
 
     const Comp = {
+      setup() {
+        _instance = currentInstance
+      },
       render() {
         return withDirectives(h(Child, { count: count.value }), [
           [